package org.apache.archiva.checksum;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import java.io.IOException;
import java.io.InputStream;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.List;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.output.NullOutputStream;
/**
* Checksum - simple checksum hashing routines.
*
* @author <a href="mailto:joakime@apache.org">Joakim Erdfelt</a>
* @version $Id: Checksum.java 647378 2008-04-12 05:20:47Z joakime $
*/
public class Checksum
{
private static final int BUFFER_SIZE = 32768;
public static void update( List<Checksum> checksums, InputStream stream )
throws IOException
{
byte[] buffer = new byte[BUFFER_SIZE];
int size = stream.read( buffer, 0, BUFFER_SIZE );
while ( size >= 0 )
{
for ( Checksum checksum : checksums )
{
checksum.update( buffer, 0, size );
}
size = stream.read( buffer, 0, BUFFER_SIZE );
}
}
protected final MessageDigest md;
private ChecksumAlgorithm checksumAlgorithm;
public Checksum( ChecksumAlgorithm checksumAlgorithm )
{
this.checksumAlgorithm = checksumAlgorithm;
try
{
md = MessageDigest.getInstance( checksumAlgorithm.getAlgorithm() );
}
catch ( NoSuchAlgorithmException e )
{
// Not really possible, but here none-the-less
throw new IllegalStateException( "Unable to initialize MessageDigest algorithm " + checksumAlgorithm.getAlgorithm()
+ " : " + e.getMessage(), e );
}
}
public String getChecksum()
{
return Hex.encode( md.digest() );
}
public ChecksumAlgorithm getAlgorithm()
{
return this.checksumAlgorithm;
}
public void reset()
{
md.reset();
}
public Checksum update( byte[] buffer, int offset, int size )
{
md.update( buffer, 0, size );
return this;
}
public Checksum update( InputStream stream )
throws IOException
{
DigestInputStream dig = new DigestInputStream( stream, md );
IOUtils.copy( dig, new NullOutputStream() );
return this;
}
}